August 17, 2015 - August 23, 2015 Breathtaking altitudes, treacherous climbs & the world’s best riders. Referred to as “America’s Race,” the USA Pro Challenge will take place August 17-23, 2015. For seven consecutive days, the world’s top athletes race through the majestic Colorado Rockies, reaching higher altitudes than they’ve ever had to endure. One of the largest cycling events in U.S. history and the largest spectator event in the history of the state, the USA Pro Challenge is back for 2015.